EP1974991A2 - Electric seat heater and seat upholstery with such a seat heater - Google Patents

Abstract

The heater has a heating conductor divided into two segments (7) that are connected by an electrical conductor (8). A plastic-foil strip (9) runs between the segments along the electrical conductor, where the plastic-foil strip is made of polyimide or PET. The plastic-foil strip is in heat conducting contact with the conductor that is a part of the conductor of heating units (10). The conductor is connected with the plastic-foil strip by an adhesive i.e. acrylate adhesive, foil.

Description

The invention relates to an electric seat heating with heating conductors, which are divided into at least two segments, wherein the two segments are connected by at least one electrical conductor. Furthermore, the invention relates to a seat upholstery with such a seat heater, wherein the padding has at least two segments which are separated by trenches and / or pockets and / or drawers, and wherein each segment comprises a heating element with heating conductors and the heating elements of the segments by at least one electrical conductors are connected.

For heating seats, seats or car seats heating elements are required, which usually consist of metallic heating elements or carbon fibers, which are applied to a textile layer or on foam materials or embedded in textile layers and / or foam materials. These heating elements are subjected to considerable mechanical stresses due to the changing loads during use of the seat, in particular during driving. In such heating elements, fractures of the heating conductors can be caused by material fatigue, which ultimately lead to failure of the heater. Wrinkling due to stretching and shifting of the heating and covering and sinking in of the lower pad, for example the foam core, promotes such a failure. Is a heating element by a Abspanngraben (this is a depression between two cushion segments) of a seat or in a movable seat depth adjustment out, so occur in particular in the area of the inlet and outlet wrinkles and high bending cycles on the heating element and the base material. Also, in the trench optionally introduced guy wire, which fixes the heat conductor down in the trench, can mechanically load the head very strong.

If the conductor is designed as a heat conductor, this generates just in narrow feedthroughs, d. H. narrow and deep furrows between two segments, high power losses and heat generation. On the one hand, in the case of narrow trenches, the heating conductor has to come in and out at almost the same point, which adds up the performance. On the other hand, at the same time the heat dissipation is strongly impeded by the pad.

To solve the problem of mechanical durability, conductors are used made of a variety of materials, such as steel or metallized plastic fibers; In addition, core-sheath wires are also in use.

Another possibility which is used is that of arranging heat conductors and contact conductors in a wave form in order to allow them to spring in and out of the waves during bending stresses. However, the Heizleitertemperatur rises sharply because a wave train outputs more heat output than a straight line, if one assumes the same current strength. A corresponding Flächenheizelement with such wavy heating conductors and contact conductors is in the DE 4101290 A1 described.

Examples in order to connect two heating elements, which are assigned separately from each other upholstery sections, via a Abspanngraben are in the DE 3544499 C1 and the DE 81737914 U1 described.

The DE 3544499 C1 is a Heizleiterverbindung between separated by a provided in the upholstery core Abspanngraben, electrically heated seat or backrest surfaces for seat heating of vehicles. In order to guide a connecting conductor through the Abspanngraben, a copper tape made of a woven or knitted fabric is proposed, on which the heating element is laid wavy. The copper band is fixed by a guying wire down into the trench and thus held on train. Woven or knitted stiffeners of plastic fibers and also of metal wires as in DE 3544499 C1 are not capable of dissipating heat as long as the wire diameter is so They are chosen to stay flexible. With thin wires, the thermal conductivity is limited because there is a lot of air between the filaments, thus improving the insulation properties.

The DE 8137914 U1 describes an electrical connection device between two Flächenheizabschnitten; Between connecting points of two electric Flächenheizelementabschnitten a multi-core conductor strand is arranged.

Other methods of stabilizing the electrical connection between two terminals of area heaters separated by a trench are reinforcements using nonwoven, felt and fabric textile materials which ultimately serve to increase the bend radius and thus the Increase bending cycle number up to a fraction.

The problem of high temperatures in the area of passage through a trench has in the past been solved almost exclusively by reducing power dissipation. This can be done by using a different, low-impedance, separate conductor for the implementation of the electrical data of the heating element. This conductor is then introduced so that the actual heating element is separated and a conductor is inserted in the separation point in the form of a bridge. Disadvantages of such solutions are the high installation costs and high additional costs incurred by this connection technology, as well as the additional material. In addition, it is problematic to close the joint again so that no corrosion occurs.

The DE 1891074 suggests the use of individually insulated filaments to connect the heating elements to avoid hot spots on incipient breaks due to repeated cycling; However, connecting these individually insulated filaments with the heating conductors designed as very expensive with the resulting disadvantages.

Object of the present invention is to connect the heating element of two heating elements with at least one electrical conductor, that this electrical conductor by a trench, a pocket or by a drawer in the form of a so-called seat depth adjustment or another highly loaded, prone to buckling Be led can, without the electrical conductor falls below a minimum bending radius; wherein such a minimum bending radius is to be maintained even if the surrounding the electrical conductor textile or foam material folds whose radii are smaller than the minimum allowable bending radius of the electrical conductor. Furthermore, the resulting localized heat should be distributed in order to reduce local temperature increases.

This object is achieved by an electric electric seat heating with heating conductors, which are divided into at least two segments, wherein the two segments are connected by at least one electrical conductor, which is characterized in that between the segments along the respective electrical conductor a plastic film strip runs.

The object is also achieved by a seat upholstery with such a seat heating, wherein the padding has at least two segments which are separated by trenches and / or pockets and / or drawers, and wherein each segment is associated with a heating element with heating conductors and the heating elements of the segments are connected by at least one electrical conductor, wherein between the segments along the respective electrical conductor runs a plastic film strip.

By a foil strip is guided with the conductor and the conductor is arranged to follow-up tire at a small distance, preferably resting directly on the film strip, the bending radius of occurring bends is essentially determined by the film strip.

Preferably, the foil strip should be in heat-conducting contact with the electrical conductor. As a result of the thermal conductivity of the film strip, the heat of the conductor which is in contact therewith is distributed and dissipated, so that the electrical conductor is cooled.

It has been found that, in particular, polyimide film strips are very well suited. Polyimide is very resistant to high bending cycles. Furthermore, the polyimides show excellent properties with respect to long-term stability and corrosion stability under the influence of moisture and high salt concentrations, such as these can occur in seats. Since the temperature resistance far exceeds 300 ° C, high heat conductor temperatures are possible without influencing the film. The thermal conductivity of the plastic causes the heat to be transported away from the conductor. Preferably, a film of polyimide should be used, which is under the name "Kapton" (Kapton is a brand name of Dupont) available.

If necessary, foil strips made of PET can also be used. PET (polyethylene terephthalate), however, shows slightly lower cycle numbers in terms of flexural fatigue and somewhat lower heat-dissipating properties compared to polyimides. Since the melting point of PET is relatively low, PET can only be used below 80 ° C.

A major advantage that film strips made of special, selected plastics have is the ability to withstand high heat conductor temperatures. For example, since the heat conductivity of a high-temperature plastic such as polyimide cools the heating conductor by contacting or adhering the strip to the heating conductor and heat can be distributed to the strip width by the heat-conducting property, trench transitions can be realized despite the heat-generating heating conductor , The surface of a plastic strip about 1 cm wide and 10 cm long, for example, is about 20 times larger than a ladder of the same length with a diameter of 2.5 mm.

If the conductor is connected to the film strip by means of adhesive technology, the conductor can not separate from the film strip and thus give off any heat that may be generated. Suitable adhesives are primarily acrylate tapes, as they retain their adhesiveness and flexibility over years and are hardly affected by salt dissolved in the water.

The film thickness should preferably be chosen so that on the one hand sets a minimum not to be exceeded bending radius and on the other subscriptions and bulges are avoided on the surface. It has been shown that film thicknesses of between 50 and 500 micrometers give good results, depending on the thickness of the conductor used and the thickness of the seat cover.

This makes it possible to lead a heat conductor without costly bridge strands and thus costly soldering and assembly technology through trenches and mechanically high stress points, which can be additionally thermally insulated or covered. The heat conductor can thus be introduced in one piece without solder joints and interruptions.

Both the electrical conductor and the film strip can be embedded between an upper and lower cover layer to thereby fix film strips and electrical conductors in position and also to isolate the electrical conductor towards the outside, in particular towards the seat surface.

The electrical conductor, as held on the plastic film strip, may be part of the heat generating heating conductors of the heating elements. Thus, the electrical conductor without interruption from heating element to heating element, running over the film strip, are performed. In another embodiment, the electrical conductor may be a heating conductor different bridge conductor, which electrically connects the heating element of the heating elements.

It has been found that materials which are used as film strips also have advantages with respect to the bending cycle as a covering around a conductor, provided that the wall thickness of the covering amounts to at least 20% of the conductor diameter.

The heat conductor can be applied by means of embroidery technology on a support. If the embroidery technique is used to apply the heating conductor, a cover layer and an adhesive layer can be dispensed with so that, for example, in the trench the overall thickness can be reduced. If the conductor is directly embroidered on the film strip, particularly good mechanical connections between the heating conductor and the film are achieved without the need to use glue.

Due to the heat distributions of the film strip and the wavy implementation without overheating is feasible.

Finally, especially with single-insulated filaments of a heat conductor, in which a trench transition is excluded by means of a separate bridge strand, the film strip a simple and effective solution. Namely, if individual insulated strands of a conductor except at their ends repeatedly electrically connected in between, the pure parallel circuit and thus the independence of the individual strands is repealed and interrupting individual filaments, the remaining filaments can be overloaded. However, each jumper wire creates such a connection when the filaments of the jumper strand are not isolated from each other.

For bridge strands, which are usually designed in a higher cross section and thus better conductivity, the power consumption is lower, so that here only the mechanical stability is improved.

Figur 1

eine schematische Darstellung der Polsterung eines Sitzes im Bereich von zwei Segmenten, die durch einen Graben getrennt sind,

Figur 2

einen Sitz, in dem die Polsterung, wie sie ausschnittsweise in Figur 1 gezeigt ist, integriert ist, und

Figur 3

einen V-förmigen Graben zwischen zwei Segmenten einer Polsterung.

Further details and features of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing. In the drawing shows

FIG. 1

a schematic representation of the upholstery of a seat in the region of two segments, which are separated by a trench,

FIG. 2

a seat in which the upholstery, as shown in detail in FIG. 1 is shown, integrated, and

FIG. 3

a V-shaped ditch between two segments of a padding.

On a vehicle seat 1, as in FIG. 2 As shown, in certain areas of the padding, trenches, cuts, depressions, and the like separate the various pad areas. Such a trench is, for example, also present between the seat 2 and the seat depth extension 3 (extension area of the seat 2) and in FIG FIG. 2 denoted by the reference numeral 4. Further depressions, cuts, and the like, between two cushion sections, are marked with the reference numeral 5.

Usually, such a vehicle seat 1 is provided with a seat heater, which is integrated in the seat in the region of the seat surface 2, but also in the region of the backrest 6 or in the region of the lateral cheeks. Such a seat heater includes heating elements with heating conductors, which are associated with the respective sections of the padding.

A problem arises in connection with the seat 1, as in FIG. 2 is shown, in that the individual seating elements or their heating conductors in the trenches 4 or recesses 5 must be electrically connected to each other. According to the invention, this, as shown in the FIG. 1 , solved in that between the segments 7 of a cushioning material of the seat 2 and the seat depth extension 3, two electrically connecting conductors 8 are provided which extend in waves. These electrical conductors 8 are placed on a plastic film strip 9, which forms a carrier.

Electrical conductor 8 and film strips 9 are in heat-conductive contact with each other and can also be glued by an adhesive, such as an acrylic adhesive tape. The film strip 9, which may have a thickness in the range of 50 to 100 microns, serves as a reinforcement for the electrical conductor 8; In addition, the film strip 9 is dimensioned so that it only allows a bending radius corresponding to the smallest, permissible bending radius of the electrical conductor 8, without this being destroyed by bending or bending stresses.

As based on the FIG. 1 can be seen, the film strip 9 is guided with the electrical conductor 8 through the trench 4 so that it rests between the two to be connected heating elements 10 which rest on a needle felt 11, which in turn is supported by the cushion segments 7, along the edges the segments 7 snuggles and extends over the bottom of the trench 4. Both the heating elements 10 and the electrical conductors 8 are covered with an insulation 12, preferably of a polyurethane film. By this type of connection of the two heating elements 10, the electrical conductors 8 are protected from mechanical fatigue due to mechanical stresses during driving and also due to the repeated adjustment of the seat depth extension 3 in their distance relative to their seat 2. In addition, due to the plastic film strip 9, the heat generated by the electrical conductor 8 during operation of the seat heating (heating elements 10) is dissipated.

FIG. 3 shows a partial view of two cushion segments 7, which are separated by a V-shaped recess 13. The two heating elements, which are not shown in detail, are in turn connected via electrical conductors 8, which are applied to a plastic film strip 9 are. Plastic film strip 9 with the electrical conductor 8 are guided to connect the heating elements through the V-shaped recess 13, so that there is a V-shaped course. In addition, the film strip 9 is held with the conductor 8 at the bottom of the V-shaped recess 13 by a tension wire 14.

The cross-sectional structure of the upholstery FIG. 3 comprises above the cushion segments 7, a first needle felt 15 and a second needle felt 16, between which the plastic foil strip 9 and the electrical conductor 8 arranged thereon are interposed and are thus insulated to the outside. The plastic film strip 9 with the electrical conductor 8 can be glued in between the two needle fleeces 15 and 16. Also in this arrangement, as in FIG. 3 is shown, the wave-shaped conductor 8 is mechanically relieved by the film strip 9, since the stresses occurring at bends and kinks are substantially absorbed by the plastic film strip 9.

While the FIGS. 1 and 3 each schematically represent a narrow film strip 9 with an undulating thereon extending electrical conductor 8, this arrangement can be changed in various ways; For example, the laying pattern of the electrical conductor can be done in a different manner, but it should be ensured that the length of the electrical conductor 8 is greater than the connecting path between the heating elements to be connected and the length of the plastic film strip 9, to which the electrical Head 8 are applied. Also, the electrical conductors 8 can be constructed of several filaments. Finally, the electrical conductor 8 can be sewn onto the film strip 9, instead of being glued to the film strip 9, by means of sewing threads.

Claims (19)

Electric seat heating with heating conductors, which is divided into at least two segments, wherein the two segments are connected by at least one electrical conductor, characterized in that between the segments (7) along the respective electrical conductor (8) a plastic film strip (9) runs. Seat heating according to claim 1, characterized in that the film strip (9) is in heat-conducting contact with the conductor (8). Seat heating according to claim 1 or 2, characterized in that the film strip (9) is formed of polyimide. Seat heating according to claim 1 or 2, characterized in that the film strip (9) is formed from PET. Seat heating according to one of claims 1 to 4, characterized in that the electrical conductor (8) with the film strip (9) is connected by an adhesive. Seat heating according to claim 5, characterized in that an acrylate adhesive tape is used as the adhesive. Seat heating according to one of claims 1 to 6, characterized in that the film strip (9) has a thickness of 50 to 500 microns. Seat heating according to one of claims 1 to 7, characterized in that the electrical conductor (8) with the film strip (9) is in direct contact. Seat heating according to one of claims 1 to 8, characterized in that both the electrical conductor (8) and the film strip (9) between an upper and / or lower cover layer (16, 15) are embedded. Seat heating according to one of claims 1 to 9, characterized in that the two heating elements (10) and the film strip (9) with the electrical conductor (8) by an upper and / or a lower cover layer (16, 15) are covered. Seat heating according to one of claims 1 to 10, characterized in that the electrical conductor (8) is part of the heat-generating heating conductors of the heating elements (10). Seat heating according to one of claims 1 to 11, characterized in that the electrical conductor (8) is formed from the heating conductor and this without interruption from heating element (10) to heating element (10) is guided. Seat heating according to one of claims 1 to 12, characterized in that the electrical conductor (8) is a heat conductor different bridge conductor, which electrically connects the heating conductors of the heating elements (10). Seat heating according to one of claims 1 to 13, characterized in that the electrical conductor (8) has an insulation made of a material which corresponds to the material of the film strip (9). Seat heating according to one of claims 1 to 14, characterized in that the heating element is applied by means of embroidery on a support. Seat heating according to one of claims 1 to 15, characterized in that the electrical conductor (8) by means of sewing thread on the film strip (9) is embroidered. Seat heating according to one of claims 1 to 16, characterized in that the electrical conductor (8) extends undulating over the film strip (9). Seat heating according to one of claims 1 to 17, characterized in that the electrical conductor (8) from a strand which has a plurality of filaments, is formed, wherein the individual filaments each carry a separate insulation. Seat padding with a seat heater according to one of claims 1 to 18, wherein the padding comprises at least two segments which are separated by trenches and / or pockets and / or drawers, and wherein each segment is associated with a heating element with heating conductors and the heating elements of the segments at least one electrical conductor are connected, wherein between the segments (7) along the respective electrical conductor (8) a plastic film strip (9) extends.

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